R. Ehrenborg

activity

19992007

most citedEhrhart-Macdonald reciprocity extended

10 citations · 10 across the 2 of their papers we have counts for

collaborators

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3 papers · 1 filter

math.CO2007

Enumerative properties of Ferrers graphs

Richard Ehrenborg, Stephanie van Willigenburg

We define a class of bipartite graphs that correspond naturally with Ferrers diagrams. We give expressions for the number of spanning trees, the number of Hamiltonian paths when ap…

math.CO2005★ 10 cited

Ehrhart-Macdonald reciprocity extended

Matthias Beck, Richard Ehrenborg

For a convex polytope P with rational vertices, we count the number of integer points in integral dilates of P and its interior. The Ehrhart-Macdonald reciprocity law gives an inti…

math.CO1999

A combinatorial proof of the log-concavity of the numbers of permutations with $k$ runs

Miklós Bóna, Richard Ehrenborg

We combinatorially prove that the number $R (n, k)$ of permutations of length $n$ having $k$ runs is a log-concave sequence in $k$ , for all $n$ . We also give a new combinatorial proo…

Enumerative properties of Ferrers graphs

Ehrhart-Macdonald reciprocity extended

A combinatorial proof of the log-concavity of the numbers of permutations with k runs

A combinatorial proof of the log-concavity of the numbers of permutations with $k$ runs